What is Jakob’s law?

A principle Jakob Nielsen describes in a text from 2000. Users spend most of their time on other websites, so they expect your website to work like the ones they know.

Who is Jakob’s law named after?

Jakob Nielsen, co-founder of Nielsen Norman Group. He wrote down the law in 2000.

Does Jakob’s law forbid new design?

No, it reminds you that novelty has a learning cost. According to NN/g, a try is worthwhile under two conditions: the new design must work clearly better once learned, and the person mustn’t leave the product before then.

Does Jakob’s law apply on mobile too?

Yes. In his 2000 text, Nielsen writes that the smaller the screen, the more important it is to stick to standard patterns.

Jakob’s Law: Meaning, Origin and an Example

In short

In Nielsen’s own words, the law is a single sentence: “Users spend most of their time on other sites.”

The consequence is in the same text. Users want your site to work like the others they already know. They use your product with what they have learned elsewhere.

This expectation is called a mental model. Try a header that contradicts this model yourself in the demo below.

Live demo: go to the cart

Both headers belong to the same store, and the products are the same too. The only difference is where the cart and menu are. First press Start task with the unfamiliar header and find the cart, then switch to the familiar one.

Find the cart

This demo works with JavaScript. If it’s off, the text below describes the same two headers in words.

Example Store is a made-up store. Time is measured from Start task to the cart. Every click in the store is counted, including clicks on empty space. Because you learn the task the first time, the second attempt is often a little faster. This isn’t a controlled experiment.

In the unfamiliar header, the cart is in a menu called “Me”, and the categories are to the left of the logo. In the familiar header, the cart sits at the top right, under its own name.

In the familiar layout, you reach the cart in one click. In the unfamiliar one, it takes at least two clicks, and often a few wrong links get tried first.

Origin: a text from 2000

Jakob Nielsen describes the law in the text “End of Web Design”, published on the NN/g website on July 22, 2000. There it is called “Jakob’s Law of the Internet User Experience”. Nielsen writes in the same text that the law had already held on the web for some years.

Nielsen founded Nielsen Norman Group together with Don Norman. He also developed the heuristic evaluation method.

The main message of the text is clear: websites should tone down idiosyncratic design and stick to standards. Nielsen says this separately for visual design, labels, interaction and information architecture. Among his examples of standardised design is the shopping cart and its small icon.

The same text also has a note on mobile devices. The smaller the screen, the more important it becomes to stick to standards for navigation and how options are shown. Nielsen also writes that people won’t use a website if they can’t figure out how it works within a few seconds.

On August 18, 2017, Nielsen explained the law again in a video titled “Jakob’s Law of Internet User Experience”.

The law is also tied to the fourth of Nielsen’s 10 usability heuristics from 1994: consistency and standards. According to today’s NN/g text, a design that contradicts expectations puts the burden of learning something new on the person.

Applying it: examples

The examples are typical and don’t target any particular website or bank. For each, I ask the same question: in which other product did the person learn this element?

1. The header of an online store

The layout I see on large online stores is very similar. The logo is on the left, search in the middle, account and cart at the top right. Users repeat this layout daily on other websites.

That is why calling the cart a “bag” or hiding it in the profile menu is expensive, even if it looks creative. The person loses time looking for the cart. Showing the number of items next to the icon is part of the same habit.

The search field carries a similar expectation. Pressing the magnifier should open a field, and Enter should bring results. For fields such as address, payment and card, the habits from the form design pattern apply.

2. The bottom bar of a banking app

Suppose someone has accounts at two banks, and in both apps “Send money” is in the bottom tab bar. What happens if a third bank puts transfers two levels deep in the hamburger menu? The person first looks for it where they know it from the other apps.

The same principle applies in a redesign. Laws of UX gives advice for this: when you make changes, give users the option to keep using the old version for a while.

When to break from the familiar

Jakob’s law doesn’t ban new ideas; it reminds you of the price. Raluca Budiu describes this price in the 2016 NN/g article on the learning curve.

According to her, staying consistent with other websites gives users another repetition of a common element. They also benefit from their practice on other websites.

Budiu recommends asking these questions before a new design:

Does the new design work clearly better than the old one once users have learned it? If not, drop it.
Will users keep using the product until they have learned it? If they leave, don’t ship the novelty.
Can you speed up learning? Showing the new design more often or making it easier to learn increases the share of people who adopt it.

According to Budiu, novelty pays off more easily in some cases. If the person can’t leave the product, as with enterprise software, they have to learn the new layout. People who use an interface several times a day also learn it quickly.

When many designers adopt the same pattern, it becomes the new standard over time. Swipe to delete and the hamburger menu on mobile became standards this way.

Budiu adds a warning: if the point where the learning curve flattens is very far away, people may never get there. Her example is Windows 8. In the end, Microsoft changed the design instead of waiting for users.

Limits and misconceptions

It has no formula like Fitts. Fitts’s law describes a measured movement time. Jakob’s law is an observation and a design rule. It gives no numeric threshold.

“Other sites” aren’t the same for everyone. The software an accountant uses every day differs from a student’s apps. Which pattern is familiar, you find out by looking at your users, not the industry average.

It doesn’t mean copying. Taking a competitor’s bad flow into your own product isn’t applying the law. The pattern should be familiar; the brand and tone stay yours.

Patterns change over time. An element that is familiar today was once new. Swipe to delete started that way too, then many apps adopted it. That is why I re-check the patterns I consider familiar with every redesign.

Internal consistency counts too. NN/g speaks of two kinds of consistency: within the product and with the industry’s patterns. If the cart is at the top right on one screen and at the bottom on another, sticking to external patterns isn’t enough.

My note

The Jakob mistake I see most often in audits: the position of basic elements is changed to make the brand stand out. The logo moves to the middle, the cart into a menu. The team sees differentiation; the person loses their way.

I look for differentiation in content and tone. The cart, search, sign-in and back button are allowed to stay boring. In a heuristic evaluation, I ask on every screen: where has the person seen this element in another product?

If you want this check done for your own product, the UX Audit also covers problems with headers, menus and consistency.

Where users’ expectations come from is described in the definition of the mental model. The consistency principle and the nine others are on the page about Nielsen’s 10 usability heuristics. The other laws are in the list of laws of UX.